Detection Of DNA Damage In Living Cells Based On Electrochemistry And Surface-Enhanced Raman Spectroscopy

8-Hydroxydeoxyguanosine(8-OHd G)is widely considered to be an important marker of cellular oxidative stress,as well as a self-repair product of DNA damage,reflecting the dynamic balance between oxidative damage and repair.Studies have found that high levels of 8-OHd G increase the risk of gene mutations and carcinogenesis,leading to chronic obstructive diseases such as hypertension,atherosclerosis,and cardiovascular.Therefore,8-OHd G is considered to be an important substance for early disease diagnosis.In this paper,a flexible Gold Nanoelectrode(f GNE)is prepared.Based on this electrode,it combines electrochemical measurement and Surface Enhanced Raman Spectroscopy(SERS)technology.It can detect guanine(G)and 8-OHd G without further modification.When f GNE performs electrochemical detection of G and 8-OHd G,it exhibits high detection sensitivity and detection resolution.By controlling the scanning speed to control the number of electrons transferred,different oxidation products can be obtained,and then the electrochemical and SERS signal of G oxidation derivatives can be discussed.The main research contents are as follows:(1)A f GNE for detecting DNA oxidative damage products of living cells and SERS activity is prepared.The f GNE has high detection sensitivity and detection resolution for DNA oxidative damage products of living cells.The detection limits of f GNE for G and8-OHd G are 5 nmol/L and 10 nmol/L,respectively.(2)After using K₂Cr O₄ and H₂O₂ with a final concentration of 20?mol/L to damage living cells,apply a bias voltage of-0.7 V to collect DNA oxidative damage products,and perform electrochemical and SERS detection to determine the production of the DNA oxidative damage products 8-OHd G and its tautomers.(3)Control the distance between f GNE and living cells and the time to collect damage products,and observe the changes in the intensity of SERS characteristic peaks to judge the changes in the amount of damage products produced.When the distance between f GNE and cell membrane increases and the time to collect damage products increases,the amount of damage products accumulates continuously.When the time of collecting DNA oxidative damage products exceeds 60 min,the amount of damage products gradually decreases due to the completion of the base self-repair process of the cells.At the same time,through the detection of African green monkey kidney cells(Vero),human cervical cancer cells(He La)and human lung cancer cells(A549)after injury,it is proved that cancer cells have more strong resistance in the face of external damage than normal cells.